1. Field of the Invention
The present invention relates to a starter for starting an engine. More particularly, the present invention relates to the a seal structure for housing window portions of the starter.
2. Related Art
The conventional starter used for starting engines included a housing having a gear chamber interlocked with external parts via a window, a drive shaft stored in the gear chamber and of which one end was rotatably supported by the housing end, and a pinion gear freely fit with the drive shaft in the gear chamber, with relative rotation and axial sliding allowed therebetween, and which engaged with a ring gear through the window during advancing.
In the above type of conventional starter, dirty water, mud and dust entered the gear chamber through the window particularly because of the rotating ring gear, and contaminants inside of the gear chamber.
Journal of Nippondenso Technical Disclosure Nos. 54-052 and 54-053 teach to resolve this problem. According to these documents, the housing window portion is shielded with a window shutter interlocked with the advancement and retraction of the pinion, so as to prevent dirty water, mud and dust, etc., from entering the gear chamber when the pinion is still or not in movement.
However, in these documents, the pinion end protrudes from the housing window when the pinion retracts. The water from the outer circumference of the pinion brought up onto the ring gear concentrates on the teeth roots of the pinion gear. This water runs along the teeth roots, and infiltrates the housing. Furthermore, these documents do not contemplate a dust-proof structure, as is desirable in a practical use.
Portions that support the output shaft with the housing end have a structure that fixes the bearings with the open holes on the housing. Foreign materials enter into these open holes.